Dedicated wireways for collar-mounted bobbin antennas

ABSTRACT

A system to protect a downhole antenna from fluid penetration, in some embodiments, comprises a collar; a bobbin antenna, mounted on the collar, including multiple coil slots on an outer surface of the bobbin antenna and including one or more intra-bobbin wireways between at least one of the coil slots and an outlet of the bobbin antenna; and a collar wireway that is dedicated to the bobbin antenna.

BACKGROUND

Learning the material properties of subsurface formations may beadvantageous for a variety of reasons. For instance, determining theresistivity of a formation is useful in estimating the amount andlocation of hydrocarbon reserves in the formation and in determining themost effective strategies for extracting such hydrocarbons. Suchformation properties may be determined using drill string loggingtools—e.g., transmitter and receiver antennas—that are deployed inmeasurement-while-drilling (MWD) applications. These tools are typicallyhoused within slots or pockets that are machined directly into the drillstring collar. Conductive wires are routed to the tools (e.g., for usein transmitter coils) via wireways housed within the drill string. Dueto the space constraints inherent in drill string collars, a singlewireway will typically be shared by two or more logging tools.

BRIEF DESCRIPTION OF THE DRAWINGS

Accordingly, there are disclosed in the drawings and in the followingdescription a collar-mountable bobbin antenna having coil and ferriteslots and a dedicated wireway for each such antenna. In the drawings:

FIG. 1 is a schematic diagram of a drilling environment.

FIG. 2 is a perspective view of a measurement-while-drilling (MWD) tool.

FIG. 3 is a perspective view of a bobbin antenna having tilted coilslots.

FIG. 4 is a side view of a bobbin antenna having tilted coil slots.

FIG. 5 is a side view of a bobbin antenna having orthogonal coil slots.

FIGS. 6A-6B are front and rear views of a bobbin antenna, respectively.

FIGS. 7A-7B are perspective views of the shells of a single bobbin.

FIGS. 8A-8B are perspective and cross-sectional views, respectively, ofcoil slots and ridges.

FIGS. 9A-9B are perspective and cross-sectional views, respectively, offerrite slots and ridges.

FIG. 10 is a cross-sectional view of an antenna tool assembly.

FIG. 11 is an expanded cross-sectional view of an antenna tool assembly.

It should be understood, however, that the specific embodiments given inthe drawings and detailed description thereto do not limit thedisclosure. On the contrary, they provide the foundation for one ofordinary skill to discern the alternative forms, equivalents, andmodifications that are encompassed together with one or more of thegiven embodiments in the scope of the appended claims.

DETAILED DESCRIPTION

A disclosed example embodiment of a collar-mountable bobbin antenna hasouter and inner surfaces on which coil and ferrite slots, respectively,are formed. The bobbin assembly is a self-contained antenna that can bemounted and removed from drill string collars with ease. In addition,the bobbin comprises a relatively inexpensive, non-conductive material(e.g., polyether ether ketone (PEEK)). Thus, compared to antennas thatare machined directly into collars, the disclosed bobbin antennaprovides a cost-efficient and easy-to-replace solution for downholemeasurement applications. Further, because the antenna is self-containedwithin the bobbin and is not machined into the collar, additional spaceis available within the collar and, therefore, additional components maybe incorporated into the collar. These additional components mayinclude, without limitation, a dedicated wireway for supplyingconductive wire to each bobbin antenna within the collar. A wireway thatis “dedicated” to an antenna is a wireway that routes conductive wire toand from that antenna and no other antenna. The dedicated nature of thewireways ensures that the breach of one wireway (e.g., due to drillingfluid penetration) does not result in damage to antennas served by otherwireways.

FIG. 1 is a schematic diagram of an illustrative drilling environment100. The drilling environment 100 comprises a drilling platform 102 thatsupports a derrick 104 having a traveling block 106 for raising andlowering a drill string 108. A top-drive motor 110 supports and turnsthe drill string 108 as it is lowered into a borehole 112. The drillstring's rotation, alone or in combination with the operation of adownhole motor, drives the drill bit 114 to extend the borehole 112. Thedrill bit 114 is one component of a bottomhole assembly (BHA) 116 thatmay further include a rotary steering system (RSS) 118 and stabilizer120 (or some other form of steering assembly) along with drill collarsand logging instruments. A pump 122 circulates drilling fluid through afeed pipe to the top drive 110, downhole through the interior of drillstring 108, through orifices in the drill bit 114, back to the surfacevia an annulus around the drill string 108, and into a retention pit124. The drilling fluid transports formation samples—i.e., drillcuttings—from the borehole 112 into the retention pit 124 and aids inmaintaining the integrity of the borehole. Formation samples may beextracted from the drilling fluid at any suitable time and location,such as from the retention pit 124. The formation samples may then beanalyzed at a suitable surface-level laboratory or other facility (notspecifically shown). While drilling, an upper portion of the borehole112 may be stabilized with a casing string 113 while a lower portion ofthe borehole 112 remains open (uncased).

The drill collars in the BHA 116 are typically thick-walled steel pipesections that provide weight and rigidity for the drilling process. Asdescribed in detail below, the bobbin antennas are mounted on the drillcollars and the collars contain dedicated wireways to route conductivewire between the bobbin antennas and processing logic (e.g., acomputer-controlled transmitter or receiver) that controls the antennas.The BHA 116 typically further includes a navigation tool havinginstruments for measuring tool orientation (e.g., multi-componentmagnetometers and accelerometers) and a control sub with a telemetrytransmitter and receiver. The control sub coordinates the operation ofthe various logging instruments, steering mechanisms, and drillingmotors, in accordance with commands received from the surface, andprovides a stream of telemetry data to the surface as needed tocommunicate relevant measurements and status information. Acorresponding telemetry receiver and transmitter is located on or nearthe drilling platform 102 to complete the telemetry link. One type oftelemetry link is based on modulating the flow of drilling fluid tocreate pressure pulses that propagate along the drill string (“mud-pulsetelemetry or MPT”), but other known telemetry techniques are suitable.Much of the data obtained by the control sub may be stored in memory forlater retrieval, e.g., when the BHA 116 physically returns to thesurface.

A surface interface 126 serves as a hub for communicating via thetelemetry link and for communicating with the various sensors andcontrol mechanisms on the platform 102. A data processing unit (shown inFIG. 1 as a tablet computer 128) communicates with the surface interface126 via a wired or wireless link 130, collecting and processingmeasurement data to generate logs and other visual representations ofthe acquired data and the derived models to facilitate analysis by auser. The data processing unit may take many suitable forms, includingone or more of: an embedded processor, a desktop computer, a laptopcomputer, a central processing facility, and a virtual computer in thecloud. In each case, software on a non-transitory information storagemedium may configure the processing unit to carry out the desiredprocessing, modeling, and display generation. The data processing unitmay also contain storage to store, e.g., data received from tools in theBHA 116 via mud pulse telemetry or any other suitable communicationtechnique. The scope of disclosure is not limited to these particularexamples of data processing units.

FIG. 2 is a perspective view of a measurement-while-drilling (MWD) tool200. The tool 200 includes a collar 202, stabilizers 204, bobbinantennas 206, 208, 210 that have tilted coil slots, and a bobbin antenna212 that has an orthogonal coil slot. Tilted and orthogonal orientationsof the coil slots are explained in detail below. The collar 202 may formpart of a bottomhole assembly (BHA), such as the BHA 116 shown inFIG. 1. The stabilizers 204 have diameters larger than those of thebobbin antennas 206, 208, 210, 212 that are positioned between thestabilizers 204, thereby limiting the impact that drill stringcollisions with the borehole wall cause to the bobbin antennas. Althoughfour bobbin antennas are shown in the tool 200 of FIG. 2, any suitablenumber of bobbin antennas may be deployed in a single tool.

FIG. 3 is a perspective view of an illustrative bobbin antenna 300. Thebobbin antenna 300 is composed of a non-conductive material, suchas—without limitation—high temperature plastics, polymers and/orelastomers (e.g., PEEK). The bobbin antenna 300 is manufactured usingany suitable technique, including known three-dimensional printingtechniques, in which a digital design file (e.g., a computer-aideddesign (CAD) file) describing the bobbin antenna is used by athree-dimensional printer to manufacture the bobbin antenna. In someembodiments, the bobbin antenna 300 includes two semi-cylindrical shells302A, 302B that couple with each other to form a cylinder, although thescope of disclosure is not limited to this particular configuration.Orifices that facilitate coupling (e.g., orifice 304) may be used tocouple the shells together—for instance, using screws and/or dowels.Coil slots 306A and ridges 306B form multiple loops around the outersurface of the bobbin antenna 300, as shown. In some embodiments, thecoil slots 306A are flush with the outer surface of the bobbin antenna300 and the ridges 306B are raised above the outer surface. In otherembodiments, such as those illustrated in the drawings, the ridges 3069are flush with the outer surface and the coil slots 306A are recessedbelow the outer surface. The precise dimensions of the coil slots 306Aand ridges 306B may vary, but in at least some embodiments, the slotsare 1.27 cm wide and 0.3175 cm deep, and the ridges are 0.127 cm wide.In the illustrative embodiment shown in FIG. 3, the coil slots 306A andridges 306B are tilted with respect to the longitudinal axis of thebobbin antenna 300. Due to the elliptical nature of the coil slots 306Aand ridges 306B formed on the outer surface of the bobbin antenna 300, aparticular tilt angle is not specified, but such a tilt angle may bespecified with respect to non-elliptical slots and ridges, such as thoseillustrated in and described with respect to FIG. 4, below.

The coil slots 306A house conductive wire and facilitate the looping ofthe conductive wire into a coil to enable the transmission and/orreception of electromagnetic signals. The ridges 306B prevent contactbetween the loops of the conductive wire so that the wire maintains alooped configuration appropriate for antenna applications. Conductivewire is routed to and from the coil slots 306A via one or moreintra-bobbin wireways, illustrated and described below with respect toFIGS. 10-11. To facilitate communications using the conductive wire coildisposed within the ridges 306B, ferrite slots 308 are formed on theinner surface of the bobbin antenna 300. The ferrite slots 308 areillustrated and described in detail below. The bobbin antenna 300 alsocomprises a prominence 310 that mates with the collar on which thebobbin antenna 300 is mounted so as to fix the position of the antenna300 relative to the collar. The prominence 310 rises from the innersurface of the bobbin antenna 300 and protrudes toward the longitudinalaxis of the antenna 300. In some embodiments, a portion (e.g., half) ofthe prominence 310 is formed on the shell 302A and half is formed on theshell 302B, although other configurations are contemplated. In someembodiments, the prominence 310 has a maximum height of approximately 1cm as measured from the inner surface of the bobbin antenna 300 towardthe longitudinal axis of the antenna 300. In some embodiments, theprominence 310 has a width of approximately 0.5 cm and a length ofapproximately 4 cm. The scope of disclosure is not limited to thespecific parameters of the prominence 310 recited herein.

In some embodiments, the thickness (i.e., the distance between the innerand outer surfaces) of the bobbin antenna 300 is approximately 1.27 cm,and the length of the bobbin antenna 300 is approximately 32.5 cm. Theseparameters may vary for different parts of an antenna and for differentantenna assemblies.

FIG. 4 is a side view of a bobbin antenna 400 having tilted coil slots.The bobbin antenna 400 includes mating shells 402A, 402B. Coil slots404A and ridges 404B are formed on the outer surface of the bobbinantenna 400. As numeral 406 indicates, the coil slots 404A and ridges404B are tilted with respect to the longitudinal axis of the bobbinantenna 400 at an approximately 120 degree angle. In other embodiments,the coil slots 404A and ridges 404B may be oriented at any othersuitable angle. The tilt angle of the conductive wire (i.e., coil)positioned within the coil slots 404A dictates the direction of theelectromagnetic field that is generated when current passes through thecoil. Similarly, as known to those of ordinary skill in the art, thepositions of the ferrite slots on the inner surface of the bobbinantenna (as described below) influence the direction of the magneticfield generated by the coil, given that the permeability of ferrite issignificantly greater than that of air (i.e., ferrite generally has ahigh relative permeability). Accordingly, the positions of the coil andferrite slots may be adjusted as necessary to produce an electromagneticfield with the desired characteristics.

FIG. 5 is a side view of a bobbin antenna 500 having orthogonal coilslots. The bobbin antenna 500 includes mating shells 502A, 502B that arecoupled to each other using screws 504. Coil slots 506A and ridges 506Bare formed on the outer surface of the bobbin antenna 500. The coilslots 506A and ridges 506B are orthogonal to the longitudinal axis ofthe bobbin antenna 500. The principle of operation across the bobbinantennas 300, 400 and 500 (FIGS. 3-5) is the same, but using differentcoil slot shapes and tilt angles results in differing electromagneticfield characteristics. Accordingly, the shapes and tilt angles of thecoil slots may be adjusted as desired to produce an electromagneticfield with the desired characteristics.

FIGS. 6A and 6B show the front and rear ends of a bobbin antenna 600,respectively. Referring to FIG. 6A, the bobbin antenna 600 has an outersurface 602 and an inner surface 604. The bobbin antenna 600 furtherincludes an intra-bobbin wireway 606 (which serves as an outlet from thebobbin wall and is described in greater detail below) through whichconductive wire is routed to and from the coil slots formed on the outersurface 602. In at least some embodiments, conductive wire passesthrough intra-bobbin wireway 608. From the intra-bobbin wireway 608, theconductive wire couples to another part of the collar assembly. Thebobbin antenna 600 also includes a prominence 610. As explained above,the prominence 610 mates with the collar so that the bobbin antenna 600remains fixed in place. FIG. 6B shows the rear end of the bobbin antenna600 with outer and inner surfaces 602, 604, respectively. Although therear end of the bobbin antenna 600 as depicted in FIG. 6B does notinclude a prominence or an intra-bobbin wireway, in at least someembodiments, the rear end may contain either or both of these features.For instance, in some embodiments, the front end of the bobbin antenna600 may include the intra-bobbin wireways and prominence as shown inFIG. 6A, while the rear end includes a prominence that mates to adifferent portion of the collar. In other embodiments, the prominencemay be positioned at the rear end in lieu of the front end. In yet otherembodiments, the intra-bobbin wireway may be located at the rear end andthe prominence at the front end. All such variations are contemplatedand thus fall within the scope of the disclosure.

FIGS. 7A-7B are perspective views of illustrative mating shells 700A,700B of a bobbin antenna, respectively. More particularly, FIGS. 7A-7Bshow the inner surfaces of the mating shells 700A, 700B. Shell 700Aincludes coil slots 702A and ridges 702B formed on its outer surface.Shell 700A further includes multiple ferrite slots 704A and ridges 704Bformed on its inner surface, as shown. The dimensions of the ferriteslots 704A may vary based on the desired electromagnetic field, but inat least some embodiments, the ferrite slots 704A have a width ofapproximately 1 cm. In some embodiments, the ferrite slots 704A areflush with the inner surface of the shell 700A, while the ridaes 704Bextend beyond the inner surface of the shell 700A. In such embodiments,the ridges 704B have a height of approximately 2.5 mm, although otherheights are contemplated. In other embodiments, the ridges 704B areflush with the inner surface of the shell 700A, while ferrite slots 704Aare recessed within the inner surface of the shell 700A. In suchembodiments, the ferrite slots 704A have a depth of approximately 2.5mm, although other depths are contemplated. Any and all such variationsfall within the scope of this disclosure.

In some embodiments, the ferrite slots 704A and ridges 704B occupy anarea of the inner surface that opposes the area of the outer surfaceoccupied by the coil slots 702A and ridges 702B, as shown. In someembodiments, the width 703 of the area of the outer surface occupied bythe coil slots 702A and ridges 702B is narrower than the width 705 ofthe area of the inner surface occupied by the ferrite slots 704A andridges 704B. The shell 700A includes dowel pin holes 706, 712 and screwholes 708, 710 that are positioned as shown so that they mate withcorresponding dowels and screws that couple to the shell 700B.

Referring now to FIG. 7B, the shell 700B is similar in many respects tothe shell 700A. The shell 700B includes coil slots 702A and ridges 702Bon its outer surface and ferrite slots 704A and ridges 704B on its innersurface. The dimensions and shapes of the slots and ridges are similarto those in shell 700A and for brevity are not repeated here. The shell700B also includes screw holes 714, 720, both of which are similar toorifice 304 (FIG. 3) in that they accommodate a screw or equivalentfastening apparatus for the purpose of coupling with a correspondinghole (e.g., screw hole) on the shell 700A. The shell 700B also comprisesdowel pin holes 716, 718, both of which accommodate a dowel orequivalent fastening apparatus for the purpose of coupling with acorresponding hole (e.g., dowel hole) on the shell 700A.

FIGS. 8A-8B are detailed perspective and cross-sectional views,respectively, of coil slots and ridges. Specifically, FIG. 8A shows aperspective view of multiple coil slots 800 and ridges 802 formed on theouter surface of a bobbin antenna. An intra-bobbin wireway 804represents the location at which the shells of the bobbin antenna coupleto each other. The intra-bobbin wireway 804 also permits the conductivewire to switch from a first coil slot 800 to a second, adjacent coilslot 800 (e.g., after having completed a full loop around the first coilslot 800). FIG. 8B shows a cross-sectional view of a single coil slot800 and adjacent ridges 802. As shown, in at least some embodiments, thecoil slot 800 and ridges 802 meet at rounded corners 804. The roundedcorners 804 improve retention strength for the coil that will bedisposed within the coil slot 800.

FIGS. 9A-9B are detailed perspective and cross-sectional views,respectively, of ferrite slots and ridges. Specifically, FIG. 9A shows aperspective view of a portion of a ferrite slots 900 and ridges 902, andFIG. 9B shows a cross-sectional view of the same. As with the coil slotsand ridges, the ferrite slots 900 and ridges 902 meet at rounded corners904.

FIG. 10 is a cross-sectional view of an antenna tool assembly 1000 thatincludes a bobbin antenna mounted on a collar that routes conductivewire to and from the coil slots of the bobbin antenna via a dedicatedcollar wireway. In particular, the assembly 1000 includes a collar 1002,a bobbin antenna 1004, ferrite ridges 1006 and ferrite slots 1008, coilridges 1010 and coil slots 1012, a fluid-resistant layer 1014 (e.g.,epoxy, resin), a protective sleeve 1016, a prominence 1018 mated to areceiving slot 1020, intra-bobbin wireways 1022, 1024, 1026, and 1028,an adapter 1030, and a dedicated collar wireway 1032. As shown, thebobbin antenna 1004 is mounted on a recessed portion of the collar 1002to permit the bobbin antenna to be protected by the fluid-resistantlayer 1014 and the sleeve 1016 and so that the total diameter of themounting (including sleeve 1016) is less than the diameter of thestabilizers 204 (FIG. 2). In this way, the bobbin antenna is protectedfrom collisions with the borehole wall. The ferrite slots 1008 containstrips of ferrite that are coupled to the slots 1008 using a suitableepoxy or resin material. Additional epoxy or resin material may beapplied as a layer between the ferrite strips and the body of the collar1002. The coil slot 1012 contains conductive wire, although theconductive wire is not expressly illustrated in FIG. 10 so that variousfeatures (including the slots 1012 and intra-bobbin wireways 1022, 1024,1026, 1028 and 1032) may be easily visualized. The fluid-resistant layer1014, which is composed of a suitable epoxy or resin material and iscommonly known in the art, protects the bobbin antenna 1004 and adapter1030 from penetration by drilling fluid when the tool 1000 is positioneddownhole. The protective sleeve 1016, also commonly known in the art,protects the bobbin antenna and adapter 1030 from mechanical damage butmay not substantially prevent fluid intrusion. Although FIG. 10 onlyshows a single prominence 1018 mated to receiving slot 1020, in someembodiments, multiple such prominences and receiving slots may be usedand they may be positioned as desired.

Conductive wire is routed between the coil slots 1012 and the adapter1030 using multiple intra-bobbin wireways. Specifically, conductive wireis provided from collar wireway 1032, through the adapter 1030, throughfluid-resistant layer 1014, and into intra-bobbin wireway 1028. In someembodiments, the conductive wire is then routed from the intra-bobbinwireway 1028, through the intra-bobbin wireway 1022 and to the coilslots 1012, where it is coiled around the outer surface of the bobbinantenna 1004. In such embodiments, the conductive wire is then routedback to the intra-bobbin wireway 1028 via intra-bobbin wireways 1024,1026, after which point the wire is passed through the adapter 1030 tothe collar wireway 1032. In other embodiments, the conductive wire isrouted from the intra-bobbin wireway 1028 through the intra-bobbinwireways 1026 and 1024 to the coil slots 1012. The wire is coiled aroundthe bobbin antenna 1004 and is then routed back to the intra-bobbinwireway 1028 via intra-bobbin wireway 1022. The wire then passes throughthe adapter 1030 to the collar wireway 1032.

FIG. 11 is an expanded cross-sectional view of the antenna tool assembly1000. As shown, the dedicated collar wireway 1032 routes the conductivewire between the adapter 1030 and a port 1034 through which the wirecouples to other components of the drill string BHA. Although a singlebobbin antenna-and-dedicated-wireway combination is shown in FIG. 11,any suitable number of bobbin antennas and corresponding, dedicatedcollar wireways may be deployed on a single collar, as intra-collarspace may permit.

Numerous other variations and modifications will become apparent tothose skilled in the art once the above disclosure is fully appreciated.It is intended that the following claims be interpreted to embrace allsuch variations, modifications and equivalents. In addition, the term“or” should be interpreted in an inclusive sense.

The present disclosure encompasses numerous embodiments. At least someof these embodiments are directed to a system to protect a downholeantenna from fluid penetration, comprising: a collar; a bobbin antenna,mounted on the collar, including multiple coil slots on an outer surfaceof the bobbin antenna and including one or more intra-bobbin wirewaysbetween at least one of the coil slots and an outlet of the bobbinantenna; and a collar wireway that is dedicated to the bobbin antenna.Such embodiments may be supplemented in a variety of ways, including byadding any of the following concepts in any sequence and in anycombination: wherein the dedicated collar wireway routes said conductivewire to a port of the collar; wherein a first one of the intra-bobbinwireways routes conductive wire between one of the coil slots and asecond one of the intra-bobbin wireways, and wherein a third one of theintra-bobbin wireways routes conductive wire between another one of thecoil slots and the second one of the intra-bobbin wireways; wherein thesecond one of the intra-bobbin wireways is formed between said outersurface of the bobbin antenna and an inner surface of the bobbinantenna; wherein the bobbin antenna further comprises anotherintra-bobbin wireway that routes conductive wire along a surface of thebobbin antenna; wherein the another intra-bobbin wireway is curved;wherein the another intra-bobbin wireway is disposed on a surface of thebobbin antenna that is on a plane orthogonal to a longitudinal axis ofthe bobbin antenna; wherein the collar wireway comprises afluid-resistant adapter that prevents fluid from penetrating the collarwireway; and further comprising a fluid-resistant material abutting thebobbin antenna.

Other embodiments are directed to a system for protecting an antennafrom drilling fluid penetration, comprising: a drill string collar;multiple bobbin antennas mounted on recessed portions of said collar,each of said multiple bobbin antennas having coil slots formed on anouter surface of said bobbin antenna; and multiple collar wirewayshoused within the collar, each of the multiple collar wireways dedicatedto a different one of the multiple bobbin antennas and containingconductive wire that couples to the coil slots of said different one ofthe multiple bobbin antennas. Such embodiments may be supplemented in avariety of ways, including by adding any of the following concepts inany sequence and in any combination: wherein each of the bobbin antennasincludes an intra-bobbin wireway for routing said conductive wire towardand away from the coil slots of said bobbin antenna; wherein theintra-bobbin wireway is disposed between the inner and outer surfaces ofa corresponding bobbin antenna; wherein each of the bobbin antennasfurther comprises another intra-bobbin wireway disposed between theinner and outer surfaces of the bobbin antenna, said anotherintra-bobbin wireway routes said conductive wire from said intra-bobbinwireway of the bobbin antenna to one of the coil slots of the bobbinantenna; wherein each of the bobbin antennas further comprises a thirdintra-bobbin wireway disposed between the inner and outer surfaces ofthe bobbin antenna, said third intra-bobbin wireway routes saidconductive wire from a different one of the coil slots of the bobbinantenna to said intra-bobbin wireway of the bobbin antenna; wherein eachof the bobbin antennas further comprises another intra-bobbin wirewaydisposed on a surface of the bobbin antenna, said another intra-bobbinwireway routes the conductive wire from the intra-bobbin wireway to thefluid-resistant material; wherein the another intra-bobbin wireway iscurved, and wherein said surface of the bobbin antenna on which theanother intra-bobbin wireway is disposed is on a plane that isorthogonal to the longitudinal axis of the bobbin antenna; wherein eachof the multiple collar wireways further comprises a fluid-resistantadapter that protects the collar wireway from fluid penetration; whereinone end of each of said multiple collar wireways couples to a port ofthe collar; further comprising a fluid-resistant material disposedwithin said recessed portions of the collar; and wherein thefluid-resistant material is flush with a surface of the collar.

The following is claimed:
 1. A system to protect a downhole antenna fromfluid penetration, comprising: a collar; a bobbin antenna, mounted onthe collar, including multiple coil slots on an outer surface of thebobbin antenna and including one or more intra-bobbin wireways betweenat least one of the coil slots and an outlet of the bobbin antenna; anda collar wireway that is dedicated to the bobbin antenna.
 2. The systemof claim 1, wherein the dedicated collar wireway routes said conductivewire to a port of the collar.
 3. The system of claim 1, wherein a firstone of the intra-bobbin wireways routes conductive wire between one ofthe coil slots and a second one of the intra-bobbin wireways, andwherein a third one of the intra-bobbin wireways routes conductive wirebetween another one of the coil slots and the second one of theintra-bobbin wireways.
 4. The system of claim 3, wherein the second oneof the intra-bobbin wireways is formed between said outer surface of thebobbin antenna and an inner surface of the bobbin antenna.
 5. The systemof claim 1, wherein the bobbin antenna further comprises anotherintra-bobbin wireway that routes conductive wire along a surface of thebobbin antenna.
 6. The system of claim 5, wherein the anotherintra-bobbin wireway is curved.
 7. The system of claim 5, wherein theanother intra-bobbin wireway is disposed on a surface of the bobbinantenna that is on a plane orthogonal to a longitudinal axis of thebobbin antenna.
 8. The system of claim 1, wherein the collar wirewaycomprises a fluid-resistant adapter that prevents fluid from penetratingthe collar wireway.
 9. The system of claim 1, further comprising afluid-resistant material abutting the bobbin antenna.
 10. A system forprotecting an antenna from drilling fluid penetration, comprising: adrill string collar; multiple bobbin antennas mounted on recessedportions of said collar, each of said multiple bobbin antennas havingcoil slots formed on an outer surface of said bobbin antenna; andmultiple collar wireways housed within the collar, each of the multiplecollar wireways dedicated to a different one of the multiple bobbinantennas and containing conductive wire that couples to the coil slotsof said different one of the multiple bobbin antennas.
 11. The system ofclaim 10, wherein each of the bobbin antennas includes an intra-bobbinwireway for routing said conductive wire toward and away from the coilslots of said bobbin antenna.
 12. The system of claim 11, wherein theintra-bobbin wireway is disposed between the inner and outer surfaces ofa corresponding bobbin antenna.
 13. The system of claim 12, wherein eachof the bobbin antennas further comprises another intra-bobbin wirewaydisposed between the inner and outer surfaces of the bobbin antenna,said another intra-bobbin wireway routes said conductive wire from saidintra-bobbin wireway of the bobbin antenna to one of the coil slots ofthe bobbin antenna.
 14. The system of claim 13, wherein each of thebobbin antennas further comprises a third intra-bobbin wireway disposedbetween the inner and outer surfaces of the bobbin antenna, said thirdintra-bobbin wireway routes said conductive wire from a different one ofthe coil slots of the bobbin antenna to said intra-bobbin wireway of thebobbin antenna.
 15. The system of claim 10, wherein each of the bobbinantennas further comprises another intra-bobbin wireway disposed on asurface of the bobbin antenna, said another intra-bobbin wireway routesthe conductive wire from the intra-bobbin wireway to the fluid-resistantmaterial.
 16. The system of claim 15, wherein the another intra-bobbinwireway is curved, and wherein said surface of the bobbin antenna onwhich the another intra-bobbin wireway is disposed is on a plane that isorthogonal to the longitudinal axis of the bobbin antenna.
 17. Thesystem of claim 10, wherein each of the multiple collar wireways furthercomprises a fluid-resistant adapter that protects the collar wirewayfrom fluid penetration.
 18. The system of claim 10, wherein one end ofeach of said multiple collar wireways couples to a port of the collar.19. The system of claim 10, further comprising a fluid-resistantmaterial disposed within said recessed portions of the collar.
 20. Thesystem of claim 19, wherein the fluid-resistant material is flush with asurface of the collar.